A basic selection
The good news about describing the world in terms of energy stores is that there are a limited number of stores to think about. Here is a selection of stores, with those that might be used earlier listed first. You'll need to become familiar with these, paying particular attention to the key features to look out for when identifying a store.
Energy stores can be more or less full
Imagine a car travelling down the road, the amount of energy in the energy store (in this case a chemical store) decreases. As changes occur, it is often the case that energy stores are filled or emptied.
It is best not to think of a store as empty or full—just as augmented or depleted by events. Augmenting and depleting stores may be a precise way of expressing matters, but we'd be surprised to find this language being useful in classrooms. So it is better to talk in terms of increasing or decreasing the energy level in a store, of filling up and emptying the store.
Here are all of the stores on single sheets:
- Firstly, more empty, ready to be filled.
- Secondly, more full, ready to be emptied.
But how do you tell if the store is being filled or emptied during a process?